Foot ulcers represent one of the most notable risk factors for lower extremity amputations in persons diagnosed with diabetes mellitus, a disorder in which blood sugar (glucose) levels are abnormally high because the body does not produce enough insulin. Persons diagnosed with diabetes are typically classified as slow healers and are prone to debilitating foot ulcers due to both neurological and vascular complications.
Peripheral neuropathy, or a deadening of the nerves, can cause altered or complete loss of tactile sensation in the foot and/or leg, and in this regard, the diabetic patient with advanced neuropathy tends to loose the ability to discriminate between sharp-dull tactile sensations. Accordingly, any cuts or trauma to the foot of a diabetic patient with advanced neuropathy often go unnoticed for lengthy periods of time, and may develop into neuropathic ulcers.
Further, a deformity commonly known as “charcot foot” occurs as a result of decreased sensation. Patients with “normal” tactile sensation in their feet automatically determine when too much pressure is being placed on an area of the foot. Once identified, the human body instinctively shifts position to relieve the stress. A patient with advanced neuropathy looses this important mechanism. As a result, tissue ischemia and necrosis, or a restriction in blood supply or a deadening of the tissue, may occur and thus lead to plantar ulcers. Microfractures in the bones of the foot thus may go unnoticed and untreated, resulting in disfigurement, chronic swelling and additional bony prominences.
Microvascular disease is an additional problem for diabetic patients, which can also lead to foot ulcers. It is well known that diabetes often results in a narrowing of smaller arteries, which narrowing cannot be resolved surgically. This microvascularization thus further prompts the diabetic patient to adhere to a strict glucose level regimen, maintain an ideal body weight and cease tobacco smoking in an attempt to reduce the onset of microvascular disease.
Should a diabetic patient develop a plantar ulcer, for whatever reason, treatment options are generally limited to a two-fold treatment plan. In the first instance, the prime objective is to obtain wound closure, which eliminates a portal of entry for bacterial invasion and development of limb-threatening infection. In the second instance, a further objective is to allow for a reduction in pressures on the foot or the “off-loading” of tissues. In this regard, protective orthotic footwear has been shown to lower sited foot pressures and further has been shown to contribute to the healing and closing of wounds. Moreover, once a given plantar ulcer has been effectively closed, protective orthotic footwear has been shown to prevent the reoccurrence of plantar ulcers.
A number of factors guide the selection of the appropriate off-loading modality for a particular patient. A few of these factors are patient compliance, comfort, ease of application, and cost. Common methods of off-loading plantar ulcers are the use of total contact casts (TCC) or lower leg walking boots otherwise known as removable cast walkers (RCW).
Removable cast walkers are often chosen in order to reduce application time and to allow the clinician to have easy access to the wound site for wound care procedures. Exemplary walkers are disclosed in U.S. Pat. Nos. 5,078,128, granted January 1992, 5,329,705, granted July 1994, and 5,378,223, granted Jan. 3, 1995, and in U.S. publication nos. 2004/0019307 and 2007/0293798, and all incorporated herein by reference. Walkers are usually quite easy to apply and remove, typically utilizing straps with VELCRO (hook and loop fasteners) or buckles.
However, the same ease with which a clinician may remove the walker in order to inspect and treat the wound site also allows patients to remove the walker outside of the presence of the clinician. Thus one concern with the use of walkers is that the healing of the ulcer will be severely compromised by patients removing the walker and ambulating without the product applied. A clinician is thus left to wonder with each application of a walker whether the patient will follow the advice of the clinician or whether the healing will be compromised by the patient removing the walker. Studies done by members of this research team and others have suggested that patients with plantar wounds secondary to diabetes only wear their off-loading device for an average of 28 percent of their daily activity.
As discussed in the paper “Evaluation of Removable and Irremovable Cast Walkers in the Healing of Diabetic Foot Wounds: A Randomized Controlled Trial,” by D. G. Armstrong et al. in Diabetes Care 28:551-554, 2005, the TCC has generally been considered the gold standard for off-loading plantar ulcers in part because it is not removable by patients. The concept of utilizing the total contact cast to treat plantar ulcers was developed in the 1950's. The total contact cast must be applied and removed by a clinician in a number of steps, as will be understood by the skilled artisan. The application is time consuming, since an inner shell of casting tape must by applied and allowed to fully dry, and then an exterior shell of casting tape is applied.
The exterior shell must typically be allowed to dry for a full 24 hours before a patient can put any weight on the TCC. Additionally, the TCC must be removed at least once every one to two weeks, if not more frequently, so that the clinician can inspect and treat the plantar ulcerations. Of course, removal of the TCC requires another application of a TCC. Thus, it seems that the use of walkers is a more efficient and economic manner of treating plantar ulcerations.
As for RCWs, while they have been have been found to be easy to use and safe to apply, a significant drawback is that patients can remove the RCW. Further, it has been found that patient compliance to these removable devices is poor. In order to force the patients to wear the RCWs, it has been proposed by D. G. Armstrong et al. to use a RCW and render it irremovable by the application of a single-layer fiberglass band. This prevents the patient from removing the RCW without notification to the clinician. Alternative methods include using a lace which can only be removed by being cut off by a tool, thereby serving as notice to the clinician that the patient has indeed removed the RCW.
From these observations, it is clear that there is a need for a device that allows easy access to wounds on the foot or ankle without removal and reapplication of the entire device. Accordingly, a RCW allowing easy access to wounds on the foot or ankle of a patient is provided that solves these and other problems associated with previous designs.
Further, there is also a need for a device that forces compliance of a walker, while still maintaining many of its benefits such as ease of application, safety of use, reduction of costs, and universality of a product. Thus, there is a need for a walker having a forced patient compliance system.